1. Field of the Invention
The present invention relates to a control device for a rotating electrical machine that controls the torque of the rotating electrical machine by operating an inverter.
2. Description of the Related Art
In recent years, brushless motors are often being used for drive motors in hybrid cars, electric cars and the like. However, unlike industrial equipment (e.g. elevators, ropeways and the like) and other electric cars (e.g. railway vehicles, trolleys and the like), automobiles provide acceleration torque for start-up from a stopped state and power for generating torque until high-speed cruising using power solely from a battery that is mounted in a limited amount of space. Therefore, extremely wide-ranging operating characteristics are required to be actualized with a compact size.
Here, to actualize the wide-ranging operating characteristics, for example, as shown in JP-A-2010-207010, a technique is proposed in which an electric motor is operated by the number of turns in a stator winding being changed as required. As described in JP-A-2010-207010, such ideas have been known since the past. However, to actualize this technique, a large number of high-capacity semiconductor switches are required, and the control device becomes complex.
Mounting becomes difficult when the technique described in JP-A-2010-207010 is used within a limited amount of space, such as within a passenger car. In fact, although practical application of the technique described in JP-A-2010-207010 is advancing in fields where the restriction on mounting space is relatively low, such as in elevators, the technique has yet to be put to practical use in automobiles.
Therefore, a control device for a rotating electrical machine capable of changing the characteristics of a stator winding with a simple configuration is desired.